JP2014030805A - Water treatment apparatus and water treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment apparatus capable of reducing exchange frequency of a treatment film, and to provide a water treatment system.SOLUTION: A water treatment apparatus includes a vessel 2 for storing an RO element 3, an introduction port 2b1 for introducing water to be treated including sea water into the vessel 2, and an adsorption member 4 for adsorbing an organic substance included in the water to be treated. The adsorption member 4 is arranged between the introduction port 2b1 and the RO element 3, and the adsorption member 4 is removable with respect to the vessel 2, and has flow-straightening function.

Description

  The present invention relates to a water treatment apparatus and a water treatment system that obtain fresh water by allowing seawater or the like to pass therethrough, for example.

  In recent years, desalination treatment systems (water treatment systems) configured to include a reverse osmosis membrane treatment device (water treatment device) using a filtration process using a reverse osmosis (RO) membrane tend to increase. Such a reverse osmosis membrane treatment apparatus is capable of obtaining fresh water by suppressing the permeation of salt by applying a pressure of at least twice the osmotic pressure to seawater and passing it through the reverse osmosis membrane. . Organic fouling is a phenomenon that reduces the permeation performance of a reverse osmosis membrane treatment apparatus. Organic fouling is fouling (clogging) caused by extracellular metabolites generated by microorganisms contained in seawater, and is a phenomenon that clogs reverse osmosis membranes.

  Such organic fouling is said to start by adsorption of a fouling-causing substance (foulant) to the membrane surface of the RO membrane, and microorganisms grow on the membrane surface using it as a bait. Therefore, in Patent Document 1, it is proposed to use a treatment membrane (RO membrane or the like) on which the supply-side channel material composed of yarns containing an antibacterial agent is laminated.

JP 2010-89081 A

  However, since the technique described in Patent Document 1 is antibacterial by introducing supply water (treated water) to the surface of the treatment membrane by the supply-side channel material, the supply water containing microorganisms or the like comes into contact with the treatment membrane. Therefore, it has been difficult to sufficiently prevent the reduction of the replacement frequency of the treatment film.

  An object of this invention is to provide the water treatment apparatus and water treatment system which can reduce the replacement frequency of a treatment membrane.

  The present invention includes a treatment unit including a reverse osmosis membrane that desalinates water to be treated containing salt, a container that houses the treatment unit, an introduction unit that introduces the water to be treated into the container, An adsorbing member that adsorbs organic matter contained in the treated water, and the adsorbing member is disposed in a container between the introduction unit and the processing unit.

  According to this, before introducing the water to be treated into the reverse osmosis membrane, the organic matter (foulant) contained in the water to be treated can be adsorbed by the adsorption member upstream of the reverse osmosis membrane. It is possible to reduce the adsorption of organic substances.

  ADVANTAGE OF THE INVENTION According to this invention, the water treatment apparatus and water treatment system which can reduce the replacement frequency of a reverse osmosis membrane can be provided.

It is an internal structure figure which shows the water treatment apparatus which concerns on this embodiment. It is a partially expanded perspective view which shows the internal structure of the RO element of a water treatment apparatus. It is a development view of the RO membrane of the RO element of the water treatment apparatus. It is a see-through | perspective perspective view which shows the reverse osmosis membrane module in which the RO element of the water treatment apparatus was integrated in the vessel. It is a front view which shows the adsorption | suction member provided in a water treatment apparatus. It is a schematic diagram which shows the flow of the fluid of a water treatment apparatus. It is a graph which shows the adsorption amount for every reagent. It is a schematic block diagram which shows the water treatment system provided with the water treatment apparatus.

  Hereinafter, a water treatment apparatus 1 according to the present embodiment and a water treatment system 100 including the water treatment apparatus 1 will be described with reference to the drawings.

  The water treatment apparatus 1 according to the present embodiment is a seawater desalination treatment system (water) that purifies reusable water such as seawater, brackish water, brine, and the like that can be reused as industrial water or drinking water. It is applied to the processing system 100). Note that “water having a relatively high salinity such as seawater, brackish water, brine, etc.” corresponds to water to be treated containing salt (hereinafter abbreviated as water to be treated).

FIG. 1 is an internal structure diagram showing a water treatment apparatus according to the present embodiment. In FIG. 1, only the inlet side into which the water to be treated of the water treatment apparatus is introduced is illustrated.
As shown in FIG. 1, the water treatment apparatus 1 includes a vessel 2 (container), a reverse osmosis membrane element (hereinafter referred to as RO element) 3, an adsorbing member 4, and the like. The RO element 3 corresponds to a processing unit including a reverse osmosis membrane.

  The vessel 2 is composed of a cylindrical body 2a and end plates 2b and 2c (see FIG. 4 for the end plate 2c) that close the axial ends of the cylindrical body 2a. The end plate 2b is configured to be detachable from an opening on the inlet side in the axial direction of the cylindrical body 2a. In addition, an introduction port 2b1 (introduction portion) through which water to be treated is introduced is formed at a position deviated from the radial center of the end plate 2b.

  In the present embodiment, the case where the inlet 2b1 is formed in the end plate 2b will be described as an example. However, as shown by a two-dot chain line in FIG. 1, instead of the inlet 2b1, the circumference of the cylindrical body 2a is described. Between the end plate 2b of the surface and the adsorbing member 4, an inlet 2a1 through which water to be treated is introduced may be formed.

  The vessel 2 is made of, for example, super stainless steel (a steel type having a PREN value (pitting corrosion coefficient) of 40 or more) that can withstand a high pressure (5 MPa or more) by a high-pressure pump 40 (see FIG. 8) described later.

FIG. 2 is a partially developed perspective view showing the internal structure of the RO element of the water treatment apparatus.
As shown in FIG. 2, the RO element 3 includes a membrane unit 10 including a reverse osmosis membrane (hereinafter referred to as RO membrane) 11 along a position corresponding to the axial center of the vessel 2 (see FIG. 1). The water collecting pipe 12 is wound around in a spiral shape.

  The membrane unit 10 includes an RO membrane 11 and spacers 13 and 14.

  The RO membrane 11 is formed in a bag shape, and the opening formed in the bag shape is bonded to the outer peripheral portion of the water collecting pipe 12. The RO membrane 11 is made of a material such as cellulose or polyamide.

  The spacer 13 is formed in a mesh shape and is disposed inside the bag-shaped RO membrane 11. The spacer 13 prevents the inner space of the RO film 11 from being crushed even when the RO film 11 is wound in a spiral shape.

  The spacer 14 is formed in a mesh shape and is disposed between the adjacent RO membranes 11 and 11. Further, the spacer 14 is bonded to the outer peripheral portion of the water collecting pipe 12 in the same manner as the RO membrane 11.

  The structure of the RO membrane 11 is not limited to the spiral type, but may be another type of structure such as a hollow fiber type.

FIG. 3 is a development view of the RO membrane of the RO element of the water treatment apparatus. FIG. 3 is a development view when the RO element 3 is viewed from the axial direction.
As shown in FIG. 3, the RO element 3 includes four bag-like RO membranes 11, 11, 11, 11, and a bag-like opening of each RO membrane 11 is formed in the outer peripheral portion of the water collecting pipe 12. The RO membrane 11 is bonded to the water collecting pipe 12 so as to communicate with the through hole 12a. The treated water supplied to the RO element 3 flows on the outer surface of the RO membrane 11 and is desalted by permeating the RO membrane 11 from the outer surface to the inner surface. Then, the desalted permeated water that has passed through the RO membrane 11 is collected from the inside of the RO membrane 11 into the water collecting pipe 12 through the bag-like opening of the RO membrane 11 and the through-hole 12a of the water collecting pipe 12. The

  The RO membrane 11 is not limited to four, and may be three or less or five or more. The shape and number of the through holes 12a can be changed as appropriate.

FIG. 4 is a perspective view showing a reverse osmosis membrane module in which the RO element of the water treatment apparatus is incorporated in a vessel.
As shown in FIG. 4, in the water treatment apparatus 1, three RO elements 3, 3, 3 are arranged in series in a vessel 2, and adjacent water collecting pipes 12 are connected to each other via a connecting pipe 15. Has been modularized. In this example, the water collecting pipe 12 of the RO element 3 located on the most upstream side is connected to the extension pipe 16 via the connecting pipe 15. The end of the extension tube 16 is closed and extends to a position penetrating the end plate 2b.

  The number of RO elements 3 is not limited to three as shown in FIG. 4, and may be two or less or four or more. Further, when applied to a water treatment system 100 (see FIG. 8) to be described later, the water treatment device 1 may use a modularized water treatment device 1 as shown in FIG. 4 alone, or The modularized water treatment apparatus 1 may be used, for example, connected in parallel, and can be appropriately changed according to the water treatment capacity required by the water treatment system 100 (see FIG. 8).

  Moreover, the piping 22 is connected to the inlet 2b1 (refer FIG. 1) formed in the end plate 2b. A drain pipe 23 for discharging concentrated water that has not permeated the RO membrane 11 is connected to the downstream end of the cylindrical body 2a. Further, a pipe 24 communicating with the water collecting pipe 12 is connected to the end plate 2 c so that permeated water collected in the water collecting pipe 12 can be taken out of the water treatment apparatus 1.

  Returning to FIG. 1, the adsorbing member 4 is disposed between the RO element 3 located on the most upstream side (frontmost stage) and the end plate 2 b in which the introduction port 2 b 1 is formed, and the adsorbing member 4 introduced from the pipe 22. It has an adsorption function for adsorbing organic substances contained in the treated water and a rectifying function for rectifying the treated water introduced from the pipe 22.

FIG. 5 is a front view showing an adsorbing member provided in the water treatment apparatus.
As shown in FIG. 5, the adsorbing member 4 has a base material 4a formed in a disk shape, and a through hole 4b penetrating in the axial direction is formed at the center of the base material 4a. A water collecting pipe is formed in the through hole 4b. 12 (refer FIG. 1) is penetrated.

  The adsorbing member 4 is configured to be detachable by removing the end plate 2b from the opening 2a2 (see FIG. 1) on the upstream side of the cylindrical body 2a (see FIG. 1). For example, the downstream end surface of the adsorption member 4 abuts on a positioning member 2d extending radially inward from the inner peripheral wall surface of the cylindrical body 2a, and is positioned at a position facing the end surface of the RO element 3 by a retaining member (not shown). ing.

  Instead of providing the positioning member 2d, the peripheral portion of the through hole 4b of the adsorption member 4 may be brought into contact with the connecting tube 15 projecting radially outward from the outer peripheral surface of the extension tube 16 for positioning. .

  Further, the adsorbing member 4 is formed with a plurality of through holes 4c penetrating in the axial direction. As the diameter (hole diameter) d of the flow hole 4c, for example, a suction member 4 having a diameter D of about 40 cm (16 inches) and a diameter of about 2.8 cm (1.1 inches) may be used. it can. In addition, although the collection rate of the organic substance (foulant: fouling cause substance) contained in to-be-processed water can be raised, so that the hole diameter d of the flow hole 4c is made small, there is a possibility that the flow hole 4c may be blocked. Therefore, in order to prevent the flow hole 4c from being blocked by fouling, it is preferable to set the hole diameter to about 5 mm (0.2 inches) or more.

  Moreover, the adsorption member 4 can be manufactured by the following method, for example. That is, the adsorption member 4 can be obtained by coating an adsorption layer suitable for adsorbing organic substances on a lotus root base material 4a formed of a material that can withstand high-pressure water to be treated.

  The base material 4a having the shape shown in FIG. 5 has a function (shape) as a single current plate. Here, the current plate has a function as an equal plate for equalizing the flow of the water to be treated introduced from the introduction port 2b1, and the water to be treated is evenly supplied to the upstream end surface of the RO element 3. It is to make it.

  In FIG. 1, a gap is formed between the outer peripheral surface of the RO element 3 and the inner peripheral surface of the vessel 2, but this is only shown in a simplified manner, and the adsorbing member 4. The total amount of the water to be treated that has passed through is introduced into the end face of the RO element 3.

  The base material 4a is not particularly limited as long as it is a material that can coat the adsorption layer, such as metal or resin, and can withstand the high pressure of the water to be treated introduced by the driving force of the high-pressure pump 40 (see FIG. 8). It is not something.

For example, the adsorbing member 4 is prepared by dissolving Al (OC ₃ H ₇ ) ₃ as a raw material of alumina in a water-ethanol solution and forming a liquid film on the surface of the base material 4a by dipping or the like. An adsorption layer can be obtained by heating. When the heat resistance of the base material 4a is low, the adsorption layer may be formed on the base material 4a by another method such as coating with a resin in which alumina powder is dispersed.

  In addition, alumina is particularly preferable as a material suitable for adsorbing organic substances, but is not limited to alumina, and for example, an aromatic polyamide that is soluble in a solution can be applied.

FIG. 6 is a schematic diagram showing the flow of fluid in the water treatment apparatus.
As shown in FIG. 6, when the water treatment apparatus 1 introduces supply water (for example, pretreated water obtained by pretreating seawater) from the introduction port 2b1 as shown by an arrow A1. The surface of the adsorbing member 4, that is, the surface 4 a 1 facing the upstream side in the axial direction of the adsorbing member 4, and the inner wall surface 4 c 1 of the flow hole 4 c are passed through. Thereby, the organic substance (foulant) contained in supply water A1 is adsorbed by the adsorbing member 4. Further, the supply water A1 that has passed through the adsorbing member 4 stays in the space Q between the adsorbing member 4 and the RO element 3, and also comes into contact with the surface 4a2 that faces the downstream side in the axial direction of the adsorbing member 4. The organic matter contained in the supply water A1 is adsorbed by the adsorbing member 4.

  Moreover, in this embodiment, since the base material 4a of the adsorption | suction member 4 has a shape which has a rectification | straightening function (equalization function), to-be-processed water introduce | transduces from the inlet 2b1 toward a part of adsorption | suction member 4. Even if it is done, the supply water A1 from the inlet 2b1 can be evenly dispersed on the upstream side of the adsorption member 4 and can be made to flow evenly through the through holes 4c of the adsorption member 4.

  In the above description, the case where the adsorbing layer is provided also on the inner wall surface 4c1 of the flow hole 4c has been described as an example. However, the inner wall surface 4c1 is not provided with the adsorbing layer on the inner wall surface 4c1. Adsorption of organic matter (foulant) onto the flow hole 4c can be reduced, and clogging (clogging) of the flow holes 4c can be reduced. Therefore, even if the hole diameter d of the flow hole 4c is made small, blockage of the flow hole 4c can be suppressed.

  Incidentally, the principle that the organic substance is adsorbed on the adsorbing member 4 is as described below. In other words, the charge of the adsorption member 4 can be charged to the plus side by passing the water to be treated (supply water) through the adsorption member 4 in which the base material 4a having a predetermined shape is coated with alumina or the like. On the other hand, since organic substances (microorganisms and particles in seawater) are negatively charged, the organic substances can be favorably adsorbed on the adsorption member 4. Incidentally, by applying the adsorbing member 4 whose surface is coated with alumina or the like, it is possible to increase the adsorbability of organic matter.

  By the way, in the water treatment apparatus 1 provided with the RO membrane 11 for seawater, it is known that organic fouling occurs in a concentrated manner on the front part of the RO element 3 and the generation in the subsequent stage is reduced. Therefore, in the water treatment apparatus 1 according to the present embodiment, the adsorption member 4 is arranged in front of the first stage (end plate 2b side) RO element 3 inserted into the vessel 2, so that the water treatment apparatus 1 includes a large amount contained in the water to be treated. It becomes possible to adsorb organic substances. That is, as in the present embodiment, by arranging the first stage RO element 3 in front of the RO element 3, the organic substance can be efficiently adsorbed with a smaller number of the adsorbing members 4 without wasting the adsorbing members 4. It becomes possible.

  Moreover, the supply water after organic substance adsorption | suction by the adsorption | suction member 4 is introduce | transduced from the end surface of RO element 3 as shown by arrow A2, and permeate | transmits RO membrane 11 (refer FIG. 2, FIG. 3), and is desalinated. Thus, as shown by an arrow B, water is collected in the water collecting pipe 12 as permeate. The permeated water B is supplied from the pipe 24 (see FIG. 4) as production water to an application according to the external water quality level.

  On the other hand, as shown by the arrow C, the supply water that has not permeated through the RO membrane 11 is gradually increased in salt concentration as it goes downstream in the vessel 2, and the salt water (concentration) having a higher salt concentration than the supply water A1. The water is discharged from the drain pipe 23 (see FIG. 4).

FIG. 7 is a graph showing the amount of adsorption for each type of reagent. The various reagents used were alumina as an example, titanium oxide and zinc oxide powders as comparative examples, and artificial seawater with hyaluronic acid added as a simulated fouling-causing substance as model seawater. And various powder was thrown into model seawater, and it stirred for 15 minutes. The stirring time is the time for the powder in the model seawater to reach equilibrium. Then, the amount of hyaluronic acid in the model seawater before stirring and the amount of hyaluronic acid in the model seawater after stirring were measured with a TOC (Total Organic Carbon) meter, and the adsorption amount (μg / m ² ) was calculated. The surface area was determined by the BET method. As shown in FIG. 7, when alumina was used, it was confirmed that the amount of adsorption was particularly superior to other metal oxides (titanium oxide, zinc oxide) shown as comparative examples.

  As described above, in the water treatment apparatus 1 of the present embodiment, the adsorbing member 4 is disposed between the introduction port 2b1 and the RO element 3, so that fouling is caused in the upstream stage (upstream side) of the RO element 3. Organic fouling can be induced in the upstream (upstream side) of the RO element 3 by collecting the organic substance as a substance and using the collected organic substance as a bait. Therefore, the replacement frequency of the RO element 3 can be reduced.

  Moreover, in the water treatment apparatus 1 of this embodiment, recontamination can be prevented by removing organic substances (fouling cause substances, foulants) immediately before the RO element 3.

  Further, when organic fouling occurs in the RO element 3, the RO element 3 cannot be cleaned well due to clogging of the RO element 3 flow path (the cleaning chemical does not flow into the closed flow path). In many cases, the effect of chemical cleaning is low). In the water treatment apparatus 1 of this embodiment, since the occurrence of organic fouling in the RO element 3 can be suppressed, blockage of the flow path can be reduced, and the effect of chemical cleaning can be prevented from being reduced. .

  Moreover, in the water treatment apparatus 1 of this embodiment, since the adsorption member 4 is detachably attached to the vessel 2, at the time of replacement, only the adsorption member 4 is removed from the vessel 2 and a new adsorption member 4 is attached. Therefore, it is not necessary to replace the entire water treatment apparatus 1, so that waste can be eliminated.

  Moreover, in the water treatment apparatus 1 of the present embodiment, the water to be treated (supply water A2: see FIG. 6) is evenly introduced into the RO membrane 11 of the RO element 3 by giving the adsorbing member 4 a rectifying function. Thus, the entire surface of the RO element 3 can be used effectively, and the adsorbing member 4 can effectively adsorb organic substances.

  Moreover, in the water treatment apparatus 1 of this embodiment, the adsorption amount of the organic substance contained in to-be-processed water can be raised by coat | covering the surface of the adsorption | suction member 4 with the material containing an alumina. As a result, organic fouling generated in the RO element 3 can be further reduced, and the replacement frequency of the RO element 3 can be further reduced.

FIG. 8 is a schematic configuration diagram illustrating a water treatment system including a water treatment apparatus.
As shown in FIG. 8, the water treatment system 100 includes a water treatment device 1, a high-pressure pump 40, a sensing unit 50, and the like.

  The high-pressure pump 40 has a capability of being driven at such a high pressure that the water to be treated (feed water A 1, A 2) reversely osmosis with respect to the RO membrane 11 of the water treatment apparatus 1. For example, the pressure of the water to be treated is increased to about 3.5 to 6 MPa by the high pressure pump 40 and supplied to the inlet 2b1 of the water treatment apparatus 1 through the pipe 41.

  A pipe 42 (main line) is connected to the suction port (introduction port) of the high-pressure pump 40, and treated water is introduced into the pipe 42. This treated water is, for example, pretreated by a pretreatment device (not shown). Examples of the pretreatment device include a UF device using an ultrafiltration membrane (UF (Ultra Filtration) membrane), an MF device using a microfiltration membrane (MF (Micro Filtration) membrane), a sand filtration device, and the like. . In this way, the taken seawater (raw water) and the like are introduced into the water treatment apparatus 1 after being treated by the pretreatment apparatus to remove the solid substances contained therein.

  The high-pressure pump 40 is controlled by the control device 200 equipped with a CPU board equipped with a CPU, ROM, RAM, etc., an input / output interface board, etc., and the drive start, drive stop, and rotation speed of the drive motor.

  The sensing unit 50 detects whether or not the adsorption member 4 is to be replaced by detecting the amount of organic matter adsorbed on the adsorption member 4 in a pseudo manner. The sensing unit 50 includes an adsorption member (not shown) similar to the adsorption member 4, and is disposed on the upstream side of the high-pressure pump 40. As described above, by arranging the sensing unit 50 upstream of the high-pressure pump 40, sensing can be performed in the low-pressure region, so that it is possible to select a plurality of sensing methods for the sensing unit 50 (the range of sensing methods is wide). ).

  The sensing unit 50 can use, for example, a mass sensor made of QCM (Quarts Crystal Microbalance), and is provided on a bypass pipe 43 (bypass line) that bypasses a part of the pipe 42. The bypass pipe 43 is provided with a velocimeter (or flow meter) 51 on the upstream side of the sensing unit 50.

  The pipe 42 is provided with a flow rate adjusting valve 44 between a connection point P1 on the upstream side of the bypass pipe 43 and a connection point P2 on the downstream side.

  The control device 200 adjusts the opening degree of the flow rate adjustment valve 44 so that the detected value (flow rate) detected by the velocimeter 51 matches the flow rate introduced into the adsorption member 4. Note that the cross-sectional area of the bypass pipe 43 is set to such a dimension that the flow velocity of the sensing unit 50 can coincide with the flow velocity introduced into the adsorption member 4. In the present embodiment, the sensing unit 50, the bypass pipe 43, the flow rate adjustment valve 44, and the control device 200 constitute an adsorption amount detection unit.

  As described above, in the water treatment system 100 of the present embodiment, the sensing unit 50 is arranged in the bypass pipe 43, and the adsorption amount of the organic substance in the adsorption member 4 is detected in a pseudo manner, whereby the main line pipes 41 and 42. Therefore, the present invention can be applied to the current water treatment system 100 without significant change.

  When the controller 200 detects the amount of adsorption of the adsorption member of the sensing unit 50 and determines that the amount of adsorption has reached the amount of adsorption that requires replacement of the adsorption member 4, the controller 200 replaces the adsorption member 4. The introduction of the water to be treated into the required water treatment apparatus 1 is stopped. Then, the end plate 2b is removed from the vessel 2, the suction member 4 is removed along the extension pipe 16, and a new suction member 4 is attached. In addition, when removing the adsorption | suction member 4, it can respond by forming the hook hook hole for exclusive use in the adsorption | suction member 4 previously, for example.

  In addition, this invention is not limited to above-described embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably. For example, a member having a rectifying function and a member having an adsorption function may be separately provided on the upstream side of the RO element 3 in the vessel 2.

1 Water treatment device 2 Vessel (container)
2a cylindrical body 2b, 2c end plate 2b1 introduction port (introduction part)
3 RO element (processing part)
4 Adsorbing member 4a Base material 4b Through hole 4c Flow hole 11 RO membrane (reverse osmosis membrane)
40 High-pressure pump (pump)
43 Bypass piping (Adsorption amount detection means)
44 Flow control valve (Adsorption amount detection means)
50 Sensing unit (adsorption amount detection means)
100 Water treatment system 200 Control device (adsorption amount detection means)
A1, A2 Supply water (treated water)
B Permeated water C Concentrated water

Claims (5)

A treatment unit equipped with a reverse osmosis membrane for desalinating water to be treated containing salt;
A container containing the processing unit;
An introduction part for introducing the treated water into the container;
An adsorbing member that adsorbs organic matter contained in the water to be treated,
A water treatment apparatus, wherein the adsorption member is disposed in a container between the introduction unit and the treatment unit.   The water treatment apparatus according to claim 1, wherein the adsorption member is detachably attached to the container.   The water treatment apparatus according to claim 1, wherein the adsorption member has a rectifying function.   The water treatment apparatus according to any one of claims 1 to 3, wherein the adsorption member is covered with a material containing alumina. The water treatment device according to any one of claims 1 to 4,
An adsorption amount detection means for detecting the adsorption amount of the organic matter adsorbed on the reverse osmosis membrane;
A water treatment system comprising: a pump provided between the water treatment device and the adsorption amount detection means, and pumping the treated water toward a reverse osmosis membrane of the water treatment device.

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